NTT Docomo 5G Wireless White Paper [pdf]

There has been a lot of discussion about 5G in the wireless industry, but we could be getting ahead of ourselves a little. To get the types of speeds being talked about, they mention spectrum above 3Ghz. Although alluded to a bit in the article, realistically to get the amount of spectrum needed (1000Mhz) they are probably going to end up in the 60Ghz band. The propagation in that band is very short, so the "densification" mentioned in the article would require a huge number of small cells, far more than is currently envisioned. One big stumbling block for some countries will be various regulatory bodies that would have to sign off on all the fiber trenching and small cell installations. Wireless backhaul is out of the question for C-RAN realistically. I think when it comes (5G) it will be only practical to deploy in dense urban areas in my view.